Problem: Recently, Anton has found a set. The set consists of small English letters. Anton carefully wrote out all the letters from the set in one line, separated by a comma. He also added an opening curved bracket at the beginning of the line and a closing curved bracket at the end of the line. 

Unfortunately, from time to time Anton would forget writing some letter and write it again. He asks you to count the total number of distinct letters in his set.

Input

The first and the single line contains the set of letters. The length of the line doesn't exceed 1000. It is guaranteed that the line starts from an opening curved bracket and ends with a closing curved bracket. Between them, small English letters are listed, separated by a comma. Each comma is followed by a space.

Output

Print a single number — the number of distinct letters in Anton's set.

Examples

Input

{a, b, c}


Output

3


Input

{b, a, b, a}


Output

2


Input

{}


Output

0

Solution (in PYTHON3):

Solution:
'''

* Author : Ayushman Chahar #
* About  : IT Sophomore    #
* Insti  : VIT, Vellore    #

'''

import os
import sys
# from collections import *
# from itertools import *
# from math import *
# from queue import *
# from heapq import *
# from bisect import *
from io import BytesIO, IOBase

BUFSIZE = 8192


class FastIO(IOBase):
    newlines = 0

    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")
readint = lambda: int(sys.stdin.readline().rstrip("\r\n"))
readints = lambda: map(int, sys.stdin.readline().rstrip("\r\n").split())
readstr = lambda: sys.stdin.readline().rstrip("\r\n")
readstrs = lambda: map(str, sys.stdin.readline().rstrip("\r\n").split())
readarri = lambda: [int(_) for _ in sys.stdin.readline().rstrip("\r\n").split()]
readarrs = lambda: [str(_) for _ in sys.stdin.readline().rstrip("\r\n").split()]


def solve():
    s = readstr()[1:-1]
    s = set(s.split(', '))
    while('' in s):
        s.remove('')
    print(len(s))


def main():
    # orig_stdin = sys.stdin
    # orig_stdout = sys.stdout
    # f1 = open("D:\\n1\\New folder\\cp\\in.txt", 'r')
    # f2 = open("D:\\n1\\New folder\\cp\\out.txt", 'w')
    # sys.stdin = f1
    # sys.stdout = f2
    t = 1
    # t = readint()
    for _ in range(t):
        # print("Case #" + str(_ + 1) + ": ", end="")
        solve()
    # sys.stdin = orig_stdin
    # sys.stdout = orig_stdout
    # f1.close()
    # f2.close()


if __name__ == "__main__":
    main()